KR20040008316A - A preparation method of Ag-doped Nano Zirconium Phosphate powders with improved antimicrobial property - Google Patents

Abstract

PURPOSE: A method for making a silver-supported zirconium phosphate powder is provided to obtain crystalline zirconium phosphate at a high yield in the form of a microparticle for use as an inorganic anti-bacterial agent. CONSTITUTION: The method for making a nano-sized silver-supported zirconium phosphate powder comprises the step of forming zirconium phosphate by an aqueous solution precipitation process using a zirconium compound and a phosphate compound. In the method, the mole ratio of P/Zr is 2.5-4. Further, the method comprises the steps of: agitating at a speed of 500-1000 rpm, washing completely with distilled water and aqueous NaOH solution, and supporting silver by using a silver compound by an ion-exchange process.

Description

A preparation method of Ag-doped Nano Zirconium Phosphate powders with improved antimicrobial property

The present invention relates to a method for preparing nano-sized silver zirconium phosphate powder having excellent antimicrobial activity, wherein the molar ratio and stirring speed of P / Zr in a method of preparing zirconium phosphate by aqueous solution precipitation using a zirconium compound and a phosphate compound Control, washing and ion exchange processes to obtain high yield and crystalline zirconium phosphate in a short time, as well as to atomize particles by homogeneous nucleation according to the increase in the stirring speed, and when used as an antimicrobial carrier, Eggplant relates to a method for producing silver ion-supported zirconium phosphate antibacterial powder.

Phosphate-based ceramics have great potential for application in many technical fields, but they are very difficult to put to practical use due to process problems [BI Lee, WD Samuel, L. Wang, GJ Exarhos, J. Mater. Res., 11 , 1 (1996)] About 40 years ago, many studies have been conducted on the application of zirconium phosphate to molecular sieves, catalysts, ion / proton conductors, and membranes.

One of the most important properties of zirconium phosphate is that it can be used as an inorganic ion exchanger. [Clearfield. A, Stynes. J, J. inorg. nucl. Chem., 26 , 117 (1964) / Alberti. S, Torraca , E. J. inorg. nucl. Chem., 30 , 317 (1968)]. These ion exchange behaviors are drawing considerable attention in that various properties can be obtained through ion exchange with various metal ions. In particular, transition metal-based ions such as Ag, Au, Pt, Cu, Zn have been confirmed in several research papers, and such inorganic antimicrobials are unlikely to promote resistance unlike conventional chemical antimicrobials. Are attracting attention in that respect (US Pat. Nos. 4,677,143, 5,409,467). In order to support the transition metal-based inorganic ions having an antimicrobial effect as described above, a carrier having an aqueous solution or an ion exchange characteristic is required. A wide range of expansion is expected and zirconium phosphate has the advantage of being able to exchange large amounts of silver ions compared to other inorganic ion exchangers. In addition, zirconium phosphate expresses excellent antimicrobial activity due to the generation of OH radicals and active oxygen in response to light radiation [Kourai. H, Manabe. Y, Yamada. Y. J. Antibact. Antifung. Agent., 22, 595-601 (1994).

In order to improve the ion exchange capacity of the crystalline zirconium phosphate powder and to increase the antibacterial properties, it is required to atomize the zirconium phosphate as a carrier.

Generally, zirconium phosphate (Zr (HPO ₄ ) ₂ .H ₂ O) has a stoichiometric ratio of P / Zr in the chemical formula of 2, but it is known that amorphous zirconium phosphate can be obtained by setting the mixing ratio of P and Zr to 2. Zirconium phosphate in the amorphous phase must be aged again in a phosphate solution for a long time to obtain crystalline zirconium phosphate. However, such a method is not only low in yield, but also requires a lot of time for powder synthesis and causes various process inconveniences. In addition, long-term aging yields particles in micrometers [Stuart E. Horsley, Derek V. Nowell, J. appl. Chem. Biotechnol. 23 , 215-224, (1973) / AI Bortun, L. N Bortun, A. Clearfield, SOLVENT EXTRACTION AND ION EXCHANGE, 15 (2) . 305-328, (1997).

In order to solve the above problems, the present inventors control the molar ratio and stirring speed of P / Zr in a method of preparing zirconium phosphate by aqueous solution precipitation using zirconium compound and phosphate compound, and establish a washing process for a short time. In addition to obtaining a high yield of crystalline zirconium phosphate, it was found that the particles were synthesized into dozens of nanoscale powders by uniform nucleation, thereby completing the present invention.

Therefore, an object of the present invention is to provide a method for preparing nano zirconium phosphate powder loaded with silver which can improve antibacterial properties when used as an inorganic antimicrobial agent.

1 is a graph showing the results of X-ray diffraction analysis of zirconium phosphate according to Comparative Examples 1 to 5 of the present invention.

2 is a graph showing the results of X-ray diffraction analysis of zirconium phosphate according to Examples 1 to 4 of the present invention.

3 is a particle size of zirconium phosphate according to Comparative Examples 6 to 8 of the present invention was measured by transmission electron microscope.

4 is a particle size of the zirconium phosphate according to Examples 5 to 7 of the present invention was measured by a transmission electron microscope.

5 is a result showing the antimicrobial activity of the silver-supported nano zirconium phosphate according to Comparative Example 9 and Example 8 of the present invention.

The present invention relates to a method for producing zirconium phosphate by the aqueous solution precipitation method using a zirconium compound and a phosphate compound, the molar ratio of P / Zr is 2.5 to 4, the step of stirring while maintaining a stirring speed of 500 to 1000 rpm and distilled water and After the complete washing step using an aqueous NaOH solution and characterized in that the method of producing a nano-size silver-supported zirconium phosphate with excellent antimicrobial power consisting of supporting silver using a silver compound by ion exchange method.

Referring to the present invention in more detail as follows.

Conventional methods [Stuart E. Horsley, Derek V. Nowell, J. appl. Chem. Biotechnol. 1973, 23, 215-224 / M. Atik, A. Pawlick., J, Mat, Sci, Cett, 14, 1486-1489, (1995) / MA Subramaian, A. Clearfield, Mat. Res. The particle size of the zirconium phosphate prepared by Bull., Vol . 19 1135-1140 is approximately 1 to 10 µm and the production time is also 150 hours to as long as 14 days or more.

Therefore, the present invention can quickly synthesize crystalline zirconium phosphate in high yield, and the resulting crystal zirconia phosphate particles also relates to a method for producing zirconium phosphate for inorganic antibacterial having a nano size.

The manufacturing method of the silver-supported nano zirconium phosphate according to the present invention is prepared using the following aqueous solution precipitation method.

First, dissolving a zirconium compound in distilled water and hydrochloric acid to prepare an aqueous solution; Dissolving a phosphoric acid compound in distilled water to prepare an aqueous solution; Mixing the P / Zr molar ratio of the aqueous zirconium solution and the aqueous phosphoric acid solution at 2.5 to 4.0 and immediately mixing the stirring speed at a speed of 500 to 1000 rpm; Filtering the resulting precipitate, washing with dilute phosphoric acid and distilled water and drying at about 50 ° C. to obtain zirconium phosphate; Washing the dried powder to pH 3 using distilled water and sodium hydroxide; The zirconium phosphate powder thus obtained is ion exchanged with an aqueous silver compound solution.

At this time, as the zirconium compound is zirconium oxychloride _{(ZrOCl 2 · xH 2 O)} , oxy-sulfate, zirconium _{(ZrOSO 4 · xH 2 O)} , zirconium oxynitrate _{(ZrO (NO 3) 2 ·} xH 2 O), zirconium nitrate ( Zr (NO ₃ ) ₄ .xH ₂ O) and zirconium sulfate (Zr (SO ₄ ) ₂ .xH ₂ O) and the like can be used. The phosphate compound includes phosphoric acid (H ₃ PO ₄ ), sodium dihydrogen phosphate (NaH ₂ PO ₄ ), disodium hydrogen phosphate (Na ₂ HPO ₄ ), sodium phosphate (Na ₃ PO ₄ ), ammonium dihydrogen phosphate (NH ₄₎ H ₂ PO ₄ ), diammonium hydrogen phosphate ((NH ₄ ) ₂ HPO ₄ ), ammonium phosphate ((NH ₄ ) ₃ PO ₄ ), potassium dihydrogen phosphate (KH ₂ PO ₄ ), dipotassium hydrogen phosphate (K ₂ HPO ₄ ), Potassium phosphate (K ₃ PO ₄ ), and the like. As the silver compound, silver nitrate (AgNO ₃ ), silver acetate (AgCH ₃ CO ₂ ), silver carbonate (Ag ₂ CO ₃ ), or the like can be used. In particular, zirconium oxychloride is preferable as the zirconium compound, and phosphoric acid is preferable as the phosphoric acid compound, and silver nitrate is used as the silver compound. If zirconium oxychloride is used as a zirconium compound, it is dissolved in hydrochloric acid. In the case of using hydrochloric acid, after completion of the reaction, washing with dilute phosphoric acid is performed to remove chlorine ions. In addition, the powder is washed with distilled water and aqueous sodium hydroxide solution to prevent aggregation of the phosphate particles by the use of excess phosphoric acid.

In particular, the present invention is prepared by mixing the zirconium compound and the phosphate compound in an aqueous solution, respectively, and the crystal form of the zirconium phosphate produced varies according to the molar ratio of the zirconium compound and the phosphate compound, so that the phosphoric acid compound 2.5 to 1 mole of the zirconium compound It is preferable to add 4.0 mol, More preferably, it is good to add 3.0-4.0 mol. If the molar ratio of P / Zr is less than 2.5, there is a problem in that zirconium phosphate having low crystallinity is generated, and if it exceeds 4.0, the yield is slightly lowered. By setting the molar ratio of P / Zr in the above range, the reaction probability of zirconium ions and phosphate is increased, so that crystalline zirconium phosphate can be obtained in high yield.

In addition, the present invention is characterized by atomizing the particle size of zirconium phosphate by controlling the stirring speed to obtain excellent physical properties when used in various fields. Since the stirring speed is a main variable controlling the homogenization of the reaction mixture, the reaction mixture is homogeneously mixed at a speed of about 500 to 1000 rpm, and simultaneous multiple nucleation proceeds in the entire solution to induce particle atomization. If the stirring speed is low, precipitation may occur only in the part where the elements are mixed in the mixing ratio of the precipitate until the homogenization proceeds, and as the homogenization proceeds, zirconium phosphate is precipitated through heterogeneous nucleation on the surface of the powder that has already been produced. The size becomes coarse.

In addition, in order to suppress the aggregation of particles occurring after the synthesis and to wash the residues, the powder synthesized in the above manner is necessarily washed to pH 3 or more through distilled water and sodium hydroxide (0.1 M NaOH) solution.

In order to ion-exchange the silver of the nano-sized crystalline zirconium phosphate, the mixture was stirred for about one day in 0.01 N AgNO ₃ aqueous solution, and then separated, washed and dried to prepare nano zirconium phosphate supported thereon.

The silver-supported zirconium phosphate according to the present invention produced through the above steps can be usefully used as an inorganic antimicrobial agent having a high antimicrobial activity by atomizing to a particle size of 20 to 30 nm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Examples 1-4

A zirconium oxychloride _{(ZrCl 2 O · 8H 2 O} ) was dissolved in 2M hydrochloric acid (HCl). A 1.3M aqueous solution of phosphoric acid (H ₃ PO ₄ ) was prepared. The two solutions were mixed such that the molar ratio of P / Zr was 2.5 (Example 1), 3 (Example 2), 3.5 (Example 3), 4 (Example 4). The reaction mixture was stirred at room temperature at a rate of about 500 rpm and maintained for 1 hour. After the reaction, the precipitated product was filtered using a vacuum filter, and washed with 0.3M aqueous solution of phosphoric acid to remove residual Cl ions and impurities. The washed zirconium phosphate was dried in a dryer at about 45-50 ° C., and the dry powder was pulverized. At this time, the obtained powder was suspended in distilled water until the pH was about 2.5, washed with 0.1M aqueous NaOH solution to pH 3, separated from the precipitate using a centrifuge, dried and pulverized to obtain a final zirconium phosphate powder. .

Comparative Examples 1 to 5

Example 1, except that the molar ratio of P / Zr is 2 (Comparative Example 1), 2.1 (Comparative Example 2), 2.2 (Comparative Example 3), 2.3 (Comparative Example 4), 2.4 (Comparative Example 5) The zirconium phosphate powder was obtained by the method similar to -4.

Test Example 1

In order to confirm the crystal phase of the zirconium phosphate prepared by Comparative Examples 1 to 5 and Examples 1 to 4, X-ray diffraction analysis (XRD) was measured, and the results are shown in FIGS. 1 and 2.

As shown in Figure 1, as shown in Comparative Examples 1 to 5 according to the present invention, it was confirmed that the zirconium phosphate increases the strength (intensity) and the more crystallization as the molar ratio of P / Zr increases. On the contrary, in Comparative Example 1, it was confirmed that amorphous zirconium phosphate was observed.

In addition, as shown in Figures 1 to 4 according to the present invention, the zirconium phosphate according to the present experiment can be seen that the complete crystal phase is obtained when the molar ratio of P / Zr is about 2.5 or more.

Examples 5-7

A zirconium oxychloride _{(ZrCl 2 O · 8H 2 O} ) was dissolved in 2M hydrochloric acid (HCl). A 1.3M aqueous solution of phosphoric acid (H ₃ PO ₄ ) was prepared. The two solutions were mixed so that the molar ratio of P / Zr was 3.5. The reaction mixture was stirred at a rate of 500 rpm (Example 5), 750 rpm (Example 6), and 1000 rpm (Example 7) at room temperature and maintained for 1 hour. After the reaction, the precipitated product was filtered using a vacuum filter, and washed with 0.3 M aqueous solution of phosphoric acid to remove Cl ions and impurities. The washed zirconium phosphate was dried in a dryer at 45 to 50 ° C., and the dry powder was pulverized to obtain a final zirconium phosphate powder.

Comparative Examples 6 to 8

Zirconium oxychloride and an aqueous solution of phosphoric acid were prepared in the same manner as in Examples 5 to 7, followed by mixing so that the molar ratio of P / Zr was 2.0. The mixture was refluxed for 72 hours in 12M phosphoric acid (Comparative Example 6), 48 hours in 12M phosphoric acid (Comparative Example 7), and 48 hours (Comparative Example 8) in 6M phosphoric acid using a reflux apparatus without stirring, followed by washing and drying. And pulverized to obtain a final zirconium phosphate powder.

Test Example 2

In order to confirm the particle size of zirconium phosphate according to the stirring speed, the zirconium phosphate prepared in Examples 5 to 7 and Comparative Examples 6 to 8 was measured by transmission electron microscope (TEM), and the results are shown in FIG. 3 and FIG. 4 is shown.

As shown in FIG. 3, the particles of zirconium phosphate obtained using a reflux apparatus without stirring show a particle size of about 0.5 to 1 μm.

However, as shown in FIG. 4, the particle size tends to be fine when proper agitation is performed during mixing of the two aqueous solutions. Example 4 having a stirring speed of 500 rpm has a particle size of 100 to 150 nm, and Example 5 having a stirring speed of 750 rpm has a particle size of 50 to 60 nm and Example 6 has a stirring speed of 1000 rpm. It was confirmed that the particle size was changed by the change of the stirring speed to 30 nm. In addition, the zirconium phosphate according to the present invention as described above was confirmed that the particles are atomized.

Example 8

Crystalline zirconium phosphate powder prepared in Example 7 was subjected to ion exchange for introducing silver ions. After weighing so that the molar ratio of Ag ions among the hydrogen ions in zirconium phosphate is 1 mol% and 10 mol%, 0.01 M AgNO ₃ aqueous solution is added to the zirconium phosphate powder prepared according to Example 7 for about one day at room temperature. Stirred. The precipitate thus obtained was centrifuged, washed with distilled water, dried and pulverized.

Comparative Example 9

The crystalline zirconium phosphate powder prepared in Comparative Example 6 was weighed so that the molar ratio of Ag ions in the hydrogen ions in the zirconium phosphate was 1 mol% and 10 mol% for the introduction of silver ions, and then 0.01 M AgNO ₃ aqueous solution was prepared. To the zirconium phosphate powder prepared by the addition was stirred vigorously for about one day at room temperature. The precipitate thus obtained was centrifuged, washed with distilled water, dried and pulverized.

Test Example 3

The antibacterial test was conducted to confirm the antimicrobial activity of the zirconium phosphate supported silver ions. 5 shows the results of measuring the antimicrobial activity of the antimicrobial powders prepared by Example 8 and Comparative Example 9 by measuring the minimum growth inhibitory concentration (MIC) of E. coli . As shown in Figure 5 it can be seen that the antimicrobial properties of the powder prepared by Example 8 than Comparative Example 9. The minimum growth inhibitory concentration was significantly reduced compared to the antimicrobial powder of Comparative Example 9 having a particle size of 20 to 30 nm and the antimicrobial powder of Example 8 having a size of 0.5 to 1 μm. That is, it can be seen that the powder having a fine particle size has high antibacterial activity. In addition, the powder on which a large amount of silver ions are loaded shows high antibacterial activity.

As described above, the zirconium phosphate according to the present invention not only obtains crystalline zirconium phosphate in high yield by controlling the molar ratio and the stirring speed of P / Zr, but also fine particles of silver ions by atomizing the particles by establishing a washing process and uniform nucleation. It can be usefully used as an inorganic antibacterial agent having excellent antibacterial properties by ion exchange of.

Claims (4)

In the method for producing zirconium phosphate by the aqueous solution precipitation method using a zirconium compound and a phosphate compound, the molar ratio of P / Zr is 2.5 to 4, the stirring rate is maintained at 500 to 1000 rpm and the distilled water and NaOH aqueous solution After the complete washing step using a method of producing a nano-sized silver-carrying zirconium phosphate having excellent antimicrobial power, characterized in that consisting of a step of supporting the silver using a silver compound by ion exchange method. The method of claim 1, wherein the zirconium compound is zirconium oxychloride _{(ZrOCl 2 · xH 2 O)} , oxy-sulfate, zirconium _{(ZrOSO 4 · xH 2 O)} , zirconium oxynitrate _{(ZrO (NO 3) 2 ·} xH 2 O), A zirconium nitrate (Zr (NO ₃ ) ₄ · xH ₂ O) or zirconium sulfate (Zr (SO ₄ ) ₂ · xH ₂ O) characterized in that the antimicrobial excellent nano-size silver-supported zirconium phosphate powder. According to claim 1, wherein the phosphate compound is phosphoric acid (H ₃ PO ₄ ), sodium dihydrogen phosphate (NaH ₂ PO ₄ ), disodium hydrogen phosphate (Na ₂ HPO ₄ ), sodium phosphate (Na ₃ PO ₄ ), phosphoric acid Ammonium Hydrogen (NH ₄ H ₂ PO ₄ ), Diammonium Hydrogen Phosphate ((NH ₄ ) ₂ HPO ₄ ), Ammonium Phosphate ((NH ₄ ) ₃ PO ₄ ), Potassium Dihydrogen Phosphate (KH ₂ PO ₄ ), Dipotassium Hydrogen Phosphate (K ₂ HPO ₄ ) or potassium phosphate (K ₃ PO ₄ ) is a method for producing nano-sized silver-supported zirconium phosphate powder with excellent antibacterial activity. The method of claim 1, wherein the silver compound is silver nitrate (AgNO ₃ ), silver acetate (AgCH ₃ CO ₂ ) or silver carbonate (Ag ₂ CO ₃ ) The production of nano-sized silver-supported zirconium phosphate powder having excellent antimicrobial activity Way.